A variable displacement expansible chamber pump has an inlet through the center chamber axis, similar to a centrifugal pump. The pump has abutments which divide a chamber which may be annular cylindrical in shape and the abutments are driven by a rotor on a different but a parallel axis, causing the sub-chambers between adjacent abutments to expand or contract. The chambers are exposed either to the intake or discharge but not both simultaneously.
The resultant pump is one having both a positive displacement pumping action as well as a kinetic pumping action. Since the device is variable displacement, zero displacement is one setting. At zero displacement the pump is a purely kinetic device. Thus at all displacement settings, the pump will have two distinct pumping disciplines.
Because the pump marries positive displacement to kinetic pumping, the flow rate is considerably increased by two means: the superimposed kinetic pumping, and the centrifugal supercharging of the expansible chambers, which allow greater rotational speeds to be attained at higher flow rates.
In fluid power applications, the increased flow rates mean increased power.
In fluid transfer applications the flow rates approach those of centrifugal devices while allowing the pressure capability of positive displacement.
The variable displacement provides versatile performance and increased efficiency.
The design is simple; of low cost of manufacture; and is silent and free of vibration.
The fields of endeavor of this invention are: fluid power, fluid (liquid) transfer, gas compressor-expander, vacuum pump.
That application was classified under art unit 3748; however, some embodiments in that case also showed characteristics not usually found in that art group. Those embodiments showed not only a positive displacement pumping ability, but also a rotary kinetic component, which when the displacement was set at zero was the only component and it was apparent from the pressure flow curves that there are two distinct curves which unite to form a single resultant curve. It was apparent from those curves that not only did the kinetic flow add to the total flow, but it also considerably extended the rotational speed of the positive displacement and thereby increased both flow and power. This application is to extend and concentrate on the hybrid nature of this technology and therefore will not only be described by art group 3748, but also have characteristics of class 415, however; class 415 specifically excludes expansible chamber pumps. This variable expansible chamber concept, when set at zero displacement, pumps purely by kinetic means, however, the intake and discharge still do not communicate which sets the device apart from other rotary kinetic pumps. In this pumping action, the momentum of the fluid carries fluid out of the discharge port and creates a partial vacuum within the chamber. The vacuum then fills as the chamber passes the intake port. At all displacement settings, there will be two distinct pumping actions, the positive displacement, and the kinetic. The higher the rotational speed, the larger the kinetic component. The higher the head pressure, the greater the positive displacement component.
This art then embraces both positive displacement pumps and rotary kinetics pump art.
Positive displacement pumps are generally regarded as high pressure, low flow devices, while centrifugal pumps are generally the opposite, having high flow rates but less pressure capability.
This hybrid pump tends to merge the two disciplines by increasing the flow of the positive displacement and at the same time maintaining the pressure capability and also allowing some high kinetic flow rates. Thus, this technology allows greater power as a result of flow times pressure. This becomes especially apparent in fluid power applications where pressures may equal the available hydraulic pumps, but flow rates may be increased by a factor of two or three and hence power is increased by the same factor. This could change fluid power applications from being auxiliary drives to being prime mover drives. In the case of fluid transfer, the technology will improve efficiency above head pressures of 25 psi, or so, as well as providing self priming and while providing high flow rates.
Prior art such as in vane pumps, shows porting which is inferior due to cavitation problems. To put the intake on the outer chamber surface causes cavitation and requires reduced angular velocity. In the case of a vane pump, the centrifugal force encountered in the suction port subtracts from the efficiency, whereas in this concept, it adds.
The general aspect of the circular chambers and simple abutments, make this a simple and high speed pump.
This pump has better suction, higher rotational speeds, greater flow rates, and more versatile performance and efficiency than existing positive displacement pumps, and as a hybrid has better performance than the smaller centrifugal pumps.
A first object is to provide a variable displacement expansible pump having an intake at the center axis and a discharge at the radially outward surface to provide the pump with a kinetic pumping component which adds to the expansible component.
A second object is to provide a pump which primes as a positive displacement, becomes largely a kinetic pump when the pump reaches the desired rotation speed, then which returns to being a positive displacement as head pressure is increased.
A third object is to provide a variable pump in which a displacement is chosen which determines a specific displacement curve; and a rotational operational speed is chosen which described a specific kinetic pumping curve; such that the resultant curve approaches an hyperbola in which the drive torque is nearly constant for most of the curve regardless of either flow or pressure.
A fourth object is to provide a pump with flexible vanes which will pass debris.
A fifth object is to provide a self priming pump which is only positive displacement in pumping a gas (air), but then becomes a kinetic pump when the pump reaches operational speed and liquid enters the pump.
A sixth object is to provide a hinged vane vacuum pump, compressor, or engine which is pressure regulated variable displacement and can have constant torque, hence higher efficiency.
A seventh object is to provide a simple pump which is similar to the variable displacement pump set at zero displacement in which the moveable abutments are removed but the porting remains the same and the pump operates as a rotary valved kinetic pump where the discharge does not communicate with the intake, but the fluid is captured within sub-chambers much as in a gear pump and the discharge is at rotor velocity.
An eighth object is to provide a simple pump as in the seventh object in which the fluid is captured in fixed chambers by centrifugal force and the discharge is tangential at rotor velocity since the pump does not have a volute.
A first advantage is a positive displacement pump with increased capacity. This is especially an advantage for fluid power applications where doubling the flow rate will double the power output.
A second advantage is in fluid transfer where the pump has flow rates approaching centrifugal rates, but is able to reach high head pressures.
A third advantage is that the regulated variable displacement can match pump load to drive load regardless of varying head pressure.
A fourth advantage is a self priming pump which after priming may be either a kinetic or positive displacement pump.
A fifth advantage is to have a kinetic pump with suction and discharge which do not communicate and is easy to prime.
A sixth advantage is to have a variable compression pump as compressor or expander in order to match to drive torque.
1 refers to a first housing member which has a rotor mounted for rotation.
2 refers to a second housing member having a chamber that is approximately annular and having a central hub.
3 refers to the rotor shaft element.
4 refers to the abutment which seals and divides the chamber.
5 refers to a fluid passage slot in the rotor drive fingers.
6 refers to the intake passage and port through the center hub in housing 2.
7 refers to the discharge passage through housing 2.
8 refers to an O-ring seal between housing 1 and housing 2.
8a refers to a seal between housing 1 and rotor shaft 3.
9 refers to a double vane abutment.
10 refers to a double vane abutment.
11 refers to a roller type abutment
11a refers to a roller type abutment designed to separate the pressure loaded surfaces and reduce spin.
12 refers to a flexible abutment having two flex surfaces.
13 refers to a pin attached to the flexible abutment 12 which is held for rotation by rotor 3
14 refers to a flexible abutment bonded to rotor element 3
15 refers to an annular groove in both housing 1 and housing 2 which engages flexible abutment 14.
16 refers to a hinged abutment which is free to rotate about the center hub.
17 refers to a swivel bearing element.
18 refers to an assembly consisting of an adjusting screw through housing 1 which contacts a spring which in turn contacts housing 2.